The objective of the current proposal is to examine the properties of information channels in the monkey visual system. We know that channels for coding color and luminance are present, and that within these there are different conduction velocity groups. We will further analyze these groups to determine whether their responses can be modelled by linear systems analysis. Three sets of data will be gathered from neurons in the paralyzed monkey LGN and striate cortex: 1) measures of response linearity, homogeneity and isotropy; 2) spatial and temporal contrast sensitivity functions to luminance and wavelength modulated lights; 3) conduction velocities of afferent input. We will attempt to relate the conduction velocities to the spatial and temporal cell properties. Finally, we will investigate the role of centrifugal control on the spatial and temporal filtering properties of LGN cells.